Chris Musson – The Sun Sept 10, 2020
SCOTTISH Government health chief Jason Leitch admitted the tests used to detect Covid cases are “a bit rubbish”, it emerged today.
The national clinical director suggested the “antigen” tests – the results from which are driving ministers’ policy – are not fully reliable as they can give positive results to people who are not infectious.
Speaking in a web Q&A for members of the business body FSB Scotland, he was asked about the different kinds of coronavirus tests available, and if businesses might be able to rapidly test workers to check if they’ve got Covid.
He replied: “Yes, I think that will come. The science is not ready for that yet. I think a number of things will happen.
“Remember, the first, the most important test we’re doing just now is the antigen test – looking for virus.
“Now, the test just now is bit rubbish.
“It is positive if it finds live virus or remnants of dead virus. It can’t tell the difference.
“So you could still be shedding virus six weeks after you’ve had the infection and still get a positive test, and you’re not infectious.
“So the test we have just now is a bit rubbish, and the science is trying to improve that test all the time.”
Mr Leitch’s comments come amid debate in the scientific community about the “false positive” and “false negative” rates for the antigen or PCR testing.
In the web Q&A, he said of the flaw in test: “That’s why you hear us talk about testing a lot. It’s very important, but it’s not the only important thing.”
Experts have since blasted the “astonishing” admission.
Professor Carl Heneghan, director of Oxford University’s Centre For Evidence-Based Medicine, said: “I think it’s an astonishing admission for the National Clinical Director to say the test they are using to direct national policy is ‘a bit rubbish’.
“I guess he’s reflecting on and questioning the whole system, because the test as it currently reports – in the context of ‘are you infectious’ or ‘have you the live virus’ – is not helpful whatsoever.”
Prof Heneghan said that “what we really need to know” is how many people are “weak positives versus actually potential infectious”.
He said: “Then the test and trace system should focus on those that are most likely to be infectious.”
An analysis by the Oxford academic and his colleagues last week suggested hospital patients with Covid could be being overcounted in Scotland
They pointed out the number of cases on wards revealed by Nicola Sturgeon at her daily briefings was at a rate nearly nine times higher than down south, and could include people who have recovered from the virus and have other illnesses.
The report prompted Ms Sturgeon to say a review of the counting system was underway.
Last week, the Centre For Evidence-Based Medicine also produced a review showing Covid PCR tests could be picking up dead cells from old infections – the issue referred to by Prof Leitch – and creating “false positives” which exaggerate the extent of the pandemic.
Prof Heneghan suggested a cut-off point so that low doses of the virus do not produce a false positive result.
Today, Prof Heneghan said: “Policy is not being driven by hospital admissions, symptomatic cases, ICU admissions, deaths.
“It’s being driven by a binary PCR Yes/No result for which your national director has just said is a ‘a bit rubbish’.
“What they are doing is reflecting their policies are based on opinions and not based on the actual evidence.
“It’s incredibly important – even in an individual case – if you’re going to make the decision to treat somebody or not, that you have an accurate test that helps you understand what actually is happening in this individual.
“Otherwise you are treating people at random for all sorts of diseases when you’re not clear if they have them.”
Labour health spokesperson Monica Lennon said: “This outburst is irresponsible and the Scottish Government should withdraw these remarks.
“Testing plays a crucial role and to dismiss this as ‘rubbish’ will undermine public confidence in the Test and Protect strategy.
“SNP Ministers should act on the advice of experts like Professor Linda Bauld who just yesterday told Parliament we need more testing.”
Scottish Conservative health spokesperson Donald Cameron said: “Given that testing is absolutely vital in stopping the spread of coronavirus, this off the cuff remark from Jason Leitch may cause some alarm.
“People need to have confidence in the testing process and be reassured that it is accurate and reliable – especially with the recent increases in people testing positive.”